Endoscope Light Emission Timing for Rolling Shutter Image Uniformity
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Solution Overview
Problem
Existing endoscope systems with rolling shutter type image sensors face issues of insufficient light amount, brightness unevenness, and lateral stripes due to varying exposure periods, which can result in distorted and unnatural images.
Innovation Solution
A light source device utilizing multiple semiconductor light emitting elements with different wavelength bands, controlled to extend or shorten light emission profiles in specific directions to manage exposure levels, ensuring sufficient light while minimizing distortion and brightness unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light source is completely turned off during the rolling shutter period, then distortion and artifacts caused by rolling shutter are avoided, but insufficient light amount occurs depending on the object
Solution Approach 1:
The patent applies periodic pulse light emission control during the rolling shutter period, emitting light in specific time intervals rather than continuously or completely turning it off. This periodic emission provides sufficient light amount while avoiding the distortion and artifacts caused by continuous illumination during the rolling shutter period.
Solution Approach 2:
The patent performs preliminary light emission during the pseudo global exposure period before the rolling shutter period begins. By pre-emitting light in this preliminary phase, the system ensures adequate illumination is established before the rolling shutter starts, reducing the need for continuous emission during the problematic rolling shutter period.
2Illumination intensity
If part of the rolling shutter period is included in the pulse light emission period, then insufficient light amount is solved, but brightness unevenness and lateral stripes occur due to exposure period difference for each line in adjacent frames
Solution Approach 1:
The patent applies different light emission strategies to different time periods: during the pseudo global exposure period, light is emitted with specific intensity and duration to ensure uniform illumination across all lines. During the rolling shutter period, light emission is controlled locally for each line based on its specific exposure timing, preventing brightness unevenness and lateral stripes while maintaining sufficient overall light amount.
3Illumination intensity
If offset light emission is performed during the rolling shutter period, then insufficient light amount is addressed, but unnatural image is generated when offset light emission becomes strong
Solution Approach 1:
The patent applies partial light emission during the rolling shutter period rather than strong or continuous emission. By controlling the light emission to be just sufficient for the exposure period without excessive intensity, the system avoids generating unnatural images while still addressing the insufficient light amount problem. The emission is precisely calibrated to match the actual exposure requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Secures adequate light levels and reduces noticeable artifacts and lateral stripes by dynamically adjusting light emission profiles, providing clearer and more natural images in endoscope systems.
Implementation Method 1
a plurality of semiconductor light emitting elements configured to emit light having different wavelength bands
Data Source
AI summary
A light source device according to the present disclosure is a light source device that generates illumination light with which an object is to be irradiated, the light source device including: a plurality of semiconductor light emitting elements configured to emit light having different wavelength bands; and a control unit configured to control a light emission profile of the plurality of semiconductor light emitting elements and drive the plurality of semiconductor light emitting elements, in which the control unit extends the light emission profile in a first direction that is a direction opposite to a direction in which time progresses in a case of increasing an exposure level and shortens the light emission profile from a second direction that is the direction in which time progresses in a case of decreasing the exposure level.